Fix result type checking of redirecting factory in checked mode (issue 6596).

tests/language/factory_redirection_test.dart

Index: tests/language/factory_redirection_test.dart
===================================================================
--- tests/language/factory_redirection_test.dart	(revision 14915)
+++ tests/language/factory_redirection_test.dart	(working copy)
@@ -63,11 +63,11 @@
   Expect.isTrue(new A<List>() is A<List>);
   Expect.isTrue(new A<bool>.constant(true).x);
   Expect.isTrue(new A<Set>.factory() is B<Set>);
-  Expect.isTrue(new B<List>.A() is A<List>);
-  Expect.isFalse(new B<List>.A() is A<Set>);
-  Expect.isTrue(new B<bool>.A_constant(true).x);
-  Expect.isTrue(new B<List>.A_factory() is B<Set>);  /// 08: dynamic type error
-  Expect.isTrue(new C<String, num>.A() is A<num>);
-  Expect.isTrue(new C<String, num>.A_factory() is B<Set>);  /// 09: dynamic type error
-  Expect.isTrue(new C<String, bool>.B_constant(true).x);
+  Expect.isTrue(new B<List>.A() is A<List>);  /// 08: dynamic type error
+  Expect.isFalse(new B<List>.A() is A<Set>);  /// 09: dynamic type error
+  Expect.isTrue(new B<bool>.A_constant(true).x);  /// 10: dynamic type error
+  Expect.isTrue(new B<List>.A_factory() is B<Set>);  /// 11: dynamic type error
+  Expect.isTrue(new C<String, num>.A() is A<num>);  /// 12: dynamic type error
+  Expect.isTrue(new C<String, num>.A_factory() is B<Set>);  /// 13: dynamic type error
+  Expect.isTrue(new C<String, bool>.B_constant(true).x);  /// 14: dynamic type error
 }